The slash in the snow, immediately forward of the wreckage, indicates that the helicopter was in a 40-degree nose-down attitude when it struck the mountain. This attitude at impact suggests that the helicopter had a loss of control, while the relatively slow speed at impact suggests that the helicopter had been in this nose-down attitude for only a short time. If the helicopter had been at a higher altitude when it turned nose-down, and had remained at this pitch for a longer time, the impact speed would have been greater. The loss of control may have been the result of a technical malfunction, or of some exterior influence such as weather conditions that limited the pilot's visual reference. The wreckage examination determined that the engine was developing power at the time of impact. Given that there was no evidence of technical malfunction with the airframe, the control systems, or any other system, weather conditions were considered. Adverse weather--such as the strong winds and whiteout conditions reported eight miles south of the accident site--probably existed throughout the Purcell Mountains and may have been encountered by the pilot en route to the alpine hut. If his visibility had been restricted by these conditions, he would have found it necessary to reduce speed. If whiteout conditions in blowing snow had caused him to lose visual reference with the ground, even momentarily, he would have faced an increased risk of losing control of the helicopter. Such a loss of control could have resulted in the nose-down attitude evident at impact. As there is no evidence of mechanical malfunction of the helicopter, its systems, or its engine, and no reports of actual site weather, nor any witnesses to the occurrence, the causal elements of this accident are undetermined.Analysis The slash in the snow, immediately forward of the wreckage, indicates that the helicopter was in a 40-degree nose-down attitude when it struck the mountain. This attitude at impact suggests that the helicopter had a loss of control, while the relatively slow speed at impact suggests that the helicopter had been in this nose-down attitude for only a short time. If the helicopter had been at a higher altitude when it turned nose-down, and had remained at this pitch for a longer time, the impact speed would have been greater. The loss of control may have been the result of a technical malfunction, or of some exterior influence such as weather conditions that limited the pilot's visual reference. The wreckage examination determined that the engine was developing power at the time of impact. Given that there was no evidence of technical malfunction with the airframe, the control systems, or any other system, weather conditions were considered. Adverse weather--such as the strong winds and whiteout conditions reported eight miles south of the accident site--probably existed throughout the Purcell Mountains and may have been encountered by the pilot en route to the alpine hut. If his visibility had been restricted by these conditions, he would have found it necessary to reduce speed. If whiteout conditions in blowing snow had caused him to lose visual reference with the ground, even momentarily, he would have faced an increased risk of losing control of the helicopter. Such a loss of control could have resulted in the nose-down attitude evident at impact. As there is no evidence of mechanical malfunction of the helicopter, its systems, or its engine, and no reports of actual site weather, nor any witnesses to the occurrence, the causal elements of this accident are undetermined. The pilot was certified and qualified for the flight in accordance with the existing regulations. The weight and centre of gravity of the helicopter were computed to have been within the allowable limits. No evidence was found of any airframe failure or system malfunction prior to, or during, the flight. The pilot may have encountered adverse weather and low visibility en route to the alpine hut, and these may have affected the pilot's ability to maintain visual contact with the ground.Findings The pilot was certified and qualified for the flight in accordance with the existing regulations. The weight and centre of gravity of the helicopter were computed to have been within the allowable limits. No evidence was found of any airframe failure or system malfunction prior to, or during, the flight. The pilot may have encountered adverse weather and low visibility en route to the alpine hut, and these may have affected the pilot's ability to maintain visual contact with the ground. The cause of this accident was not determined.Causes and Contributing Factors The cause of this accident was not determined.